1200 ■ A MANUAL OF ANATOMY 



Action. — To elevate the inferior maxilla. The superficial portion 

 also draws it slightly forwards. 



Relations — Superficial. — ^The parotid gland and Stensen's duct, 

 branches of the facial nerve, the transverse facial artery, the 

 risorius, and the platysma myoides. Deep. — ^The ramus of the 

 infarior maxilla, and the masseteric nerve and artery. The anterior 

 border overlaps the buccinator, from which it is separated by the 

 buccal pad of fat. 



Temporal Muscle — Origin. — (i) The temporal fossa, extending as 

 high as the inferior temporal ridge of the frontal and parietal 

 bones, and as low as the infratemporal crest on the external surface 

 of the great wing of the sphenoid, but excluding the portion of 

 the fossa formed by the malar bone ; and (2) the deep surface of 

 the temporal fascia over its upper part. 



Insertion.— {1) The internal surface, summit and anterior 

 border of the coronoid process of the inferior maxilla; and (2) the 

 elongated triangular surface on the internal surface of the ramus 

 of the inferior maxilla, close within the anterior border, and ex- 

 tending as low as a point on the inner side of the last molar 

 alveolus. 



Nerve-supply. — ^The deep temporal nerves, usually three in 

 number, which are branches of the anterior portion of the inferior 

 maxillary division of the fifth cranial nerve, and which enter the 

 deep surface of the muscle. 



The muscle is fan-shaped. The anterior fibres descend almost 

 vertically ; the middle fibres pass obliquely downwards and for- 

 wards ; and the posterior fibres pass forwards almost horizontally. 



Action. — ^To raise the inferior maxilla, that is, to draw it upwards 

 into contact with the superior maxilla, as in closing the mouth. 

 The posterior fibres also retract the inferior maxilla, and act in 

 opposition to the external pterygoid, which protracts it. 



RelSitions—Superficial. — ^The temporal fascia, supporting the 

 attrahens and attolleris auriculam muscles ; the superficial tem- 

 poral artery, auriculo-temporal nerve, and temporal branches of 

 the facial nerve ; the zygoma ; and fat, which is continuous with 

 the buccal pad. Deep. — ^The temporal fossa, the deep temporal 

 arteries and nerves, and the external pterygoid muscle. 



The long buccal nerve passes downwards and forwards under 

 cover of the muscle close to the anterior border of the ramus of 

 the inferior maxilla, and the masseteric nerve and artery pass out- 

 wards close to the posterior border in the region of the sigmoid notch 

 of the inferior maxilla. 



For the temporal fascia, see Index. 



External Pterygoid — Origin — (i) Upper Head. — ^The zygomatic 

 division of the outer surface of the great wing of the sphenoid, 

 below the infratemporal crest. (2) Lower Head. — ^Tlie outer surface 

 of the external pterygoid plate of the sphenoid. The upper head 

 is small, and the lower head is of large size. 



Insertion. — (i) The depression on the front of the neck of the 



